Many occupations require repetitive hand motion and/or repetitive use of hand tools, such as pliers, knives, screwdrivers, and cutting snips. Recently, there has been significant attention to, and increased reporting of, cumulative trauma disorders (CTD's) which may be related to such repetitive hand motion. One CTD, for example, is carpal tunnel syndrome. This syndrome includes swelling of the median nerve, or thickening of the carpal ligament in the hand. The physiology of this syndrome is described in more detail in U.S. Pat. No. 4,774,966.
Diagnostic devices have been developed for testing forces exerted by the hand. These devices include, for example, a carpal tunnel syndrome screening device, U.S. Pat. No. 4,774,966; a grip rate measurement, U.S. Pat. No. 4,949,729; and a human hand load sensor, U.S. Pat. No. 5,125,270. The devices in these patents are specially designed test pieces of equipment for measuring forces by the hand of a person. Since these pieces of equipment are not similar to workplace tools, the tests do not provide data which reflects conditions which are encountered by a worker in a working environment. These devices typically test controlled individual movements over a short period of time, but do not provide information regarding extended repetitive use which is more typical of the workplace.